CMOS technology has evolved such that the computer market has rapidly opened up to a wide range of consumers. Today's multi-media computer uses 64 MB main memory typically with 64 Mb Dynamic Random Access Memories (DRAMs). In the near future, 1 GB main memory will become commonplace, which will suggest a potentially strong research and development for 1 Gb DRAMs and beyond, with extremely deep sub-micron technology. Despite the main memory density requirement, it is even more important in the memory marketplace to have non-volatile memory features in a system. The typical NVRAMs (Non-Volatile Random Access Memory) are a mask-ROM, an EPROM (Electrically Programmable Read Only Memory), or a flash-RAM, and used for ID, BIOS, or core of the O/S (Operating System). These NVRAMs, however, have a unique and different standard from the DRAM standard used for a main memory configured with DRAMs. This results in copying the information stored in the NVRAM to the DRAM during the system initialization phase. A DRAM compatible flash-RAM allows for direct execution, which is an ideal solution. It is, however, inflexible to configure the density of the chip, since it had been pre-determined in the chip design. The unused bits are difficult to use for a general purpose main memory because of a poor write-speed and a limited endurance.